import Control.Applicative
import Data.Bool (bool)

main :: IO ()
main = solve <$> f >>= mapM_ putStrLn
  where
    f = map read <$> words <$> getLine

solve :: [Int] -> [String]
solve [a, b] = [bool "NO" "YES" (a + 1 <= b), (show . abs) (a + 1 - b)]